It has a great UI (material design), and the UX makes sense (the dashboard shows you a summary of your resources, resources are organized by project, notification/status icon animates when resources are changing, etc). Going back to the AWS dashboard feels clunky.
There aren't a million different image types for each region and zone - simple, autoupdated base images are available for Ubuntu, CoreOS, etc.
It has easy to understand base machine types and custom machine types with tailored specs can be created if needed. Product/service naming is clear (ex. Compute Engine vs EC2, Cloud Storage vs S3).
Addons like one-click secure web SSH sessions and Cloud Shell are amazing, no more key pairs to worry about.
Google Container Engine, with a hosted Kubernetes master, is a great concept and more transparent than closed source AWS ECS.
Their on-demand per minute pricing with sustained usage discounts is almost always significantly cheaper than AWS on demand instances, and your discounts are given automatically. Try the two calculators for yourself: Google (https://cloud.google.com/products/calculator/), AWS (https://calculator.s3.amazonaws.com/index.html).
Also, I have seen Google engineers all over HN (look at the comments on this post!) and other sites responding, commenting, and blogging - they seem actively engaged while I have seen very little from AWS.
That is not to say GCP is without problems. AWS IAM is still superior - it is easier to grant access to specific services for specific users, or have an account for a web server to upload to S3. Part of that is due to the fact that there is more plug-and-play tooling available for AWS today - boto comes to mind (boto GCP integration isn't as seamless as with AWS), as well as WAL-E. AWS's new certificate manager with free, auto-renewed SSL certs and installation on EC2 is awesome. S3 is cheaper than Google Cloud Storage. AWS has a longer free tier.
Luckily, tools like Terraform allow us to mix and match services from each cloud.